Page 22 -- SKIN COLOR (continued)

In equatorial regions of Africa, Latin America and India, where there is a high degree of sun exposure, many of the indigenous people have highly pigmented and thick skins that protect them from the harmful rays of the sun - very dark skin offers about 30 times more protection against the sun than pale skin does.    There is not, however, a definite relationship between skin pigmentation and the degree of exposure to sunlight. There are people with unexpected skin colors for the area in which they live. For example, the Tasmanian Australoids are dark-skinned although they live in a temperate latitude; also the pigmentation of American Indians, who are descendants of Asian peoples, is similar across the whole continent of North America. These examples are probably the result of migrations forty or fifty thousand years ago. A few thousand years ago, unknown factors triggered a great migration of people from east to west. The native peoples of central and western Europe were pushed   westwards. Among these were the original Celts (people with blue eyes and very pale skins easily burnt by the sun), who eventually populated parts of Scotland and Ireland; their descendants can still be identified in those countries.    Similarly, in the last few hundred years peoples with white skins have migrated to Australia and South Africa - areas of high sunshine to which their skins are not well adapted, and among them sun damage and skin cancer rates are high.    Some skin types appear to show specific and curious adaptations to their climate. Many Scandinavian people have pale skins and light hair in winter. In the short but sunny summer, many of them tan quite markedly and quickly while their hair bleaches to almost white.    In the last few centuries, increasing ease of travel and the creation of multinational countries such as the USA have led to a wide range of different shades of skin and hair types and colors among the world's population.